This invention relates to a device to be used to input data to a computer, and more particularly to a pointing device to be used to control the movement of a cursor on a display screen. In particular the invention concerns itself with a rolling/sliding type pointing device in which a sliding cylinder is used for moving the cursor.
When data on a desired two-dimensional position are to be provided to a computer, it has been conventional practice in the past to use various pointing devices such as a mouse or trackball so as to dispose the cursor in overlying relationship with respect to a specific position on the display screen.
The mouse has come into wide use because, in order to input the aforesaid data to the computer, the mouse is simple to use such that it has only to be moved on the top of a desk. Two types of mice are known, one of which is a mechanical mouse having a ball on its underside that can roll in all directions. Rollers within the mouse ride on the ball so as to be contra-rotated thereon so that the direction the ball is rolling and the number of revolutions thereof may be detected and provided to the computer as the direction in which the mouse is moving and the distance by which the mouse moves. Another type is an optical mouse, which requires a special mousepad that has a grid drawn thereon. This mousepad is irradiated by a laser to detect the mouse""s movement. The aforesaid direction and distance to be provided to the computer are found from the pattern of light beams reflected from the mousepad.
Essentially, the trackball is a mouse lying on its back, with a portion of the rotatably mounted ball exposed above the upper surface of the body. To move the cursor, the ball is rotated with a thumb, fingers, or the palm of a hand.
The mouse has the disadvantage that it requires much space to use it on the top of the desk and gives rise to an operational difficulty with limited space at an operator""s disposal. The trackball has the disadvantage that it makes it difficult to quickly input positional information by rectilinearly moving the cursor.
Input devices designed to eliminate both of the aforesaid disadvantages are disclosed in Japanese Utility Model Examined Publications Nos. 3-9061 to 3-9063. An important feature of these input devices is that a shaft is rotatably supported by the casing of a keyboard and extends through a cylinder such that the shaft allows the cylinder to be slidable thereon but renders the same non-rotatable relative to said shaft. Detectors are arranged to detect, respectively, the distance by which the cylinder is axially moved and the number of revolutions thereof. A position on the display screen is represented by X and Y, where X is determined by the distance by which the cylinder is axially moved and Y is determined by the number of revolutions of the cylinder.
Basically, any of the aforesaid input devices is constructed as shown in FIG. 8. A shaft 11 is journaled in suitable bearings 10 in the casing 9 of a keyboard. As will be apparent from FIG. 9, the shaft 11 has a middle portion 11a of oval shape in cross section, which extends through a cylinder 12 such that the middle portion 11a allows the cylinder to be slidable thereon. Consequently, the cylinder 12 can be moved in its axial direction as indicated by an arrow B along the middle portion 11a of the shaft 11 on one hand, and can be rotated about the axis of the shaft 11 as indicated by an arrow C in FIG. 9 on the other hand. First and second rotatable wheels 13 and 14 connected respectively with first and second encoders 15 and 16 abut against the cylindrical surface of the cylinder 12 such that the axes of these rotatable wheels intersect orthogonally and the axis of the second rotatable wheel 14 is disposed in parallel relation with the axis of the shaft 11. Consequently, the first rotatable wheel 13 is rotated when the cylinder 12 is subjected to a rectilineal motion in the direction of the arrow B, while the second rotatable wheel 14 is rotated when the cylinder 12 is subjected to a rotary motion in the direction of the arrow C.
The aforesaid input devices have a disadvantage that the cylinder 12 cannot provide a sufficient and constant slip in contact with the shaft 11. A cylinder 12 enlarged for the purpose of having a wide dynamic range affects the desired slip property adversely. On the other hand, a cylinder 12 which is of comparatively small diameter causes an operator to have a sense of uneasiness in rotating it, because it has to be rotated together with the shaft 11. In addition, force to be exerted on a cylinder 12 by the operator""s thumb and fingers when the cylinder 12 is to be moved in its axial direction is different in magnitude from force to be exerted when the cylinder 12 is to be rotated about the axis of the shaft 11. An operational difficulty caused thereby makes it difficult to control the movement of the pointer. The aforesaid input devices have another disadvantage that they are rather complicated to manufacture, because contact type means are used for detecting the distance by which the cylinder 12 is axially moved and the number of revolutions thereof.
One of the primary objects of the invention is to provide an improved input device which incorporates the advantageous features of prior art devices without suffering from their disadvantages. The improved input device takes the form of a rolling/sliding type pointing device which does not require much space to use it, eliminates difficulties encountered in case of the trackball in rectilinearly moving the cursor, substantially facilitates the control over the movement of the cursor with a thumb and/or fingers, affords a wide dynamic range, and may be either incorporated in or separated from the keyboard.
Another object of the invention is to provide a rolling/sliding type pointing device incorporating a roller which, when detached from a recessed fitting provided for receiving the same, can be used as a stylus for input.
The first of the foregoing objects is attained by means of a rail connected with a casing, a hollow roller rotatably and axially slidably carried on the rail, and noncontact means such as photoelectric means for detecting the direction in, and the distance by, which the hollow roller is axially moved and for detecting the direction in which the hollow roller is rotated and the number of revolutions thereof.
The first of the foregoing objects is attained also in a way different from the above, i.e., by means of a recessed fitting connected with a casing, a roller rotatably and axially slidably received in the recessed fitting, and noncontact means such as photoelectric means for detecting the direction in, and the distance by, which the roller is axially moved and for detecting the direction in which the roller is rotated and the number of revolutions thereof.
The aforesaid rail or recessed fitting takes the place of the shaft used in the prior art devices, and has excellent slip properties both when allowing the roller to be axially moved and when allowing it to be rotated. The provison of noncontact means such as photoelectric means for detecting the direction in, and the distance by, which the roller is axially moved and for detecting the direction in which the roller is rotated and the number of revolutions thereof results in rendering the detecting means free from friction and permitting a compact arrangement requiring less space. The two-dimensional position of the cursor on the display screen is determined by the distance by which the roller is axially moved and by the number of revolutions of the roller.
The invention is herein described with reference to the drawings which schematically illustrate preferred embodiments of the invention.